Defining Male and Female Act of 2025
- Sponsor
- Sen. Marshall, Roger [R-KS]
- Committees
- Judiciary Committee (primary)
- Last action
- Mar 26, 2025
Bottom line
This bill codifies a strictly biological, immutable definition of sex into federal law, explicitly excluding gender identity as a legal replacement for sex, which would mandate a reevaluation of all federal policies and regulations.
What it actually does
This bill amends Chapter 1 of title 1, United States Code, to establish statutory definitions for "sex," "male," "female," and related terms (boy, girl, man, woman, father, mother) based on immutable biological classification at conception, specifically tied to reproductive function. Crucially, it explicitly states that "gender identity" shall not be recognized by the Federal Government as a replacement for sex, as it is deemed disconnected from biological reality.
Proponents argue
Supporters argue that the bill provides essential clarity and consistency in federal law, ensuring that legal distinctions based on sex align with objective biological reality. They contend this is vital for protecting the rights and opportunities of biological females in contexts such as sports, single-sex spaces, and accurate data collection, thereby preventing confusion and maintaining fairness.
Opponents contend
Opponents contend that this bill is discriminatory and harmful, effectively erasing the legal recognition and existence of transgender and intersex individuals under federal law. They argue it would codify definitions that undermine civil rights protections, create widespread confusion, and lead to legal challenges in areas where gender identity is currently recognized or accommodated.
The bill text is exceptionally short and straightforward, making it very accessible for a reader to understand its explicit provisions and proposed changes to federal law.
Section 2, adding 1 U.S.C. 9(3)
Definition of 'Female' based on biological reproductive function
This provision defines "female," when referring to a natural person, as a person belonging, at conception, to the sex characterized by a reproductive system with the biological function of producing eggs (ova). This establishes a specific, immutable biological definition of female for all federal law and regulations.
Supporters argue
Supporters argue this definition provides clear, objective criteria for identifying females, which is essential for maintaining fairness in women's sports, ensuring accurate health data, and protecting spaces designated for biological women.
Critics contend
Opponents contend this definition is exclusionary and harmful to transgender women, denying their lived identity and potentially stripping them of protections or access to services intended for women, thereby undermining their civil rights.
Tradeoffs
The bill seeks to balance the desire for biological clarity in law with concerns about the inclusion and recognition of transgender individuals and their self-identified gender.
Section 2, adding 1 U.S.C. 9(6)
Definition of 'Male' based on biological reproductive function
This provision defines "male," when referring to a natural person, as a person belonging, at conception, to the biological sex characterized by a reproductive system with the biological function of producing sperm. This establishes a specific, immutable biological definition of male for all federal law and regulations.
Section 2, adding 1 U.S.C. 9(9)
Definition of 'Sex' as immutable biological classification
This provision defines "sex," when referring to a natural person's individual's sex, as the person's immutable biological classification as either male or female, as biologically determined and defined by this section. This reinforces the biological basis and immutability of sex in federal law, making it the overarching principle for all sex-based classifications.
Section 2, adding 1 U.S.C. 9(4)
Federal Non-recognition of 'Gender Identity' as a replacement for sex
This provision defines "gender identity" as an internal and subjective sense of self, disconnected from biological reality and sex. Crucially, it states that because such an identity does not provide a meaningful basis for identification for purposes of Federal law, the term shall not be recognized by the Federal Government as a replacement for sex. This explicitly prohibits federal agencies from using gender identity in place of biological sex.
Section 2, adding 1 U.S.C. 9(1), (2), (5), (7), (8), (10)
Definitions of 'Boy,' 'Girl,' 'Man,' 'Woman,' 'Father,' and 'Mother'
This provision defines "boy" as a minor human male, "girl" as a minor human female, "man" as an adult human male, "woman" as an adult human female, "father" as a male parent, and "mother" as a female parent. These definitions are consequential because they derive directly from the bill's core biological definitions of male and female, ensuring consistency across related terms in federal law.